Re: [PATCH v2 3/5] ARM: topology: Update cpu_power according to DT information

On Tue, 19 Jun 2012 10:28:54 +0200, Vincent Guittot wrote:

Use cpu compatibility field and clock-frequency field of DT to estimate the capacity of each core of the system and to update the cpu_power field accordingly. This patch enables to put more running tasks on big cores than on LITTLE ones. But this patch doesn't ensure that long running tasks will run on big cores and short ones on LITTLE cores.

Signed-off-by: Vincent Guittot vincent.guittot-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org

[snip]

+static void __init parse_dt_topology(void) +{

• struct cpu_efficiency *cpu_eff;
• struct device_node *cn = NULL;
• unsigned long min_capacity = (unsigned long)(-1);
• unsigned long max_capacity = 0;
• unsigned long capacity = 0;
• int alloc_size, cpu = 0;
• alloc_size = nr_cpu_ids * sizeof(struct cpu_capacity);
• cpu_capacity = (struct cpu_capacity *)kzalloc(alloc_size, GFP_NOWAIT);
• while ((cn = of_find_node_by_type(cn, "cpu"))) {

• const u32 *rate, *reg;
  

• char *compatible;
  

• int len;
  

• if (cpu >= num_possible_cpus())
  

• 	break;
  

• compatible = of_get_property(cn, "compatible", &len);
  

Why is this line needed?

• for (cpu_eff = table_efficiency; cpu_eff->compatible; cpu_eff++)
  

• 	if (of_device_is_compatible(cn, cpu_eff->compatible))
  

• 		break;
  

• if (cpu_eff->compatible == NULL)
  

• 	continue;
  

• rate = of_get_property(cn, "clock-frequency", &len);
  

• if (!rate || len != 4) {
  

• 	pr_err("%s missing clock-frequency property\n",
  

• 		cn->full_name);
  

• 	continue;
  

• }
  

• reg = of_get_property(cn, "reg", &len);
  

• if (!reg || len != 4) {
  

• 	pr_err("%s missing reg property\n", cn->full_name);
  

• 	continue;
  

• }
  

• capacity = ((be32_to_cpup(rate)) >> 20)
  

• 	* cpu_eff->efficiency;
  

Why did you break this line?

Thanks, Namhyung